The article presents the elaboration of the quasiglobal radiation model, which was implemented for the whole Slovenia. The energy received by the Sun is influenced mostly on incidence angle of the Sun, which is defined by astronomical parameters and geomorphology. Meteorological conditions, especially duration of solar radiation, have large influence on solar energy also. Virtual Sun motion over digital elevation model was simulated with equations derived from astronomical almanac. Corresponding meteorological parameters were also integrated in the model. Shade determination was considerer as an important part of the model because if a part of the surface is in the shadow, it receives less energy as sunny surface. All calculations were done for hours and decades - the annual quasiglobal radiation energy was calculated as the sun of all energies over all decades.